In the design of metalized thin film capacitors and composite current collectors, the thickness of the dielectric film directly determines the volumetric efficiency of the device - the thinner the film, the greater the capacitance per unit volume, and the lighter the weight of the device. Over the past few decades, the thickness of PET film has gradually decreased from the early 50 μ m and 25 μ m to 12 μ m and 6 μ m, and now it has advanced to 4 μ m or even 3.1 μ m. 6 μ m is at the core of this ultra-thin range - maintaining sufficient mechanical strength to support mass production and processing, while achieving significant benefits in thinning and thinning.

What is the concept of 6 μ m? As a reference, the diameter of a standard adult hair is approximately 60-80 μ m. The thickness of 6 μ m PET film is only about one tenth of the diameter of a hair. At this scale, PET film faces significant process challenges in coating, slitting, and winding processes, but has mature mass production capabilities.

2、 Vacuum evaporation: "growing" nanoscale aluminum layer on a 6 μ m substrate

The aluminum layer preparation of 6 μ m PET aluminum plated film adopts vacuum evaporation process - in a highly vacuum environment, high-purity aluminum is heated to the evaporation temperature (about 1200-1400 ° C), and the aluminum vapor is condensed and deposited on the surface of the high-speed running PET film, forming a layer of metallic aluminum. The thickness of the aluminum layer is usually in the range of 20-100 nanometers (200-1000 Å). The vacuum evaporation process can accurately control the thickness and uniformity of the aluminum layer, ensuring stable material properties. Advanced Institute Technology achieves nanoscale control of aluminum layer thickness by precisely regulating the evaporation rate and substrate operating speed of vacuum coating equipment.

Vacuum deposition on ultra-thin substrates with a thickness of 6 μ m faces a series of technical challenges that are far more stringent than conventional thickness substrates:

3、 6 μ m PET substrate: the "volume efficiency" revolution of capacitors

PET is one of the most common dielectric materials in metallized film capacitors. PET film has a high dielectric constant and excellent self-healing properties, with a working temperature of up to 120 ° C. Ultra thin PET aluminum plated film with a thickness of 6 μ m or less is the standard specification for capacitor grade metalized films. The typical thickness of capacitor grade PET film is 6-23 μ m, with a thickness tolerance of ± 5% or more.

The core engineering value of 6 μ m PET substrate lies in its volumetric efficiency. The capacitance of a capacitor is inversely proportional to the thickness of the dielectric - the thinner the film, the greater the capacitance within the same volume. For thin film capacitors that require stable operation in high current and high ripple scenarios, a 6 μ m ultra-thin PET substrate can achieve higher capacitance density in a limited space.

4、 6 μ m PET substrate: a "lightweight engine" for composite current collectors

The application of 6 μ m PET aluminum coated film in the field of lithium battery composite current collectors is one of the most concerned technological directions in recent years.

Traditional lithium battery positive electrode current collectors use aluminum foil. The composite aluminum foil adopts a sandwich structure of "double-sided aluminum plating on polymer base film" - with a 6 μ m thick PET film in the middle and aluminum plating layers on both sides. The key advantages of composite aluminum foil are reflected in three dimensions:

5、 Aluminum layer thickness: from OD 0.12 to OD 1.0- fine control of performance

Based on a 6 μ m PET substrate, aluminum plated film products with different aluminum layer thicknesses can be prepared by precisely controlling the evaporation process parameters. The thickness of the aluminum layer (characterized by optical density OD value) ranges from 0.12 to 1.0, and different thicknesses correspond to different performance focuses:

Note: The higher the optical density (OD) value, the thicker the aluminum layer, and the higher the barrier and reflectivity. The thickness of the aluminum layer is usually in the range of 20-100 nanometers.

6、 Key performance: 6 μ m specification technical confidence

7、 Core application scenarios: from capacitors to composite current collectors

8、 Selection considerations: from OD values to application scenarios

9、 Conclusion

The essence of 6 μ m PET aluminum coated film is an engineering product that combines the thinning and thinning of PET film with mature mass production processes. It is not simply "thinning" - at the 6 μ m scale, material tension control, temperature management, pinhole suppression, and coating uniformity all face engineering challenges that are far more stringent than conventional thickness substrates. It is precisely these boundary conditions that have been overcome one by one that enable the 6 μ m PET aluminum coated film to move from the laboratory to mass production, becoming the core material for applications such as metalized thin film capacitors, lithium battery composite current collectors, and precision electronics.

From improving the volumetric efficiency of thin film capacitors to upgrading the safety of lithium battery composite current collectors, the 6 μ m PET aluminum plated film is transforming the simple engineering goal of "thinner" into tangible performance improvements and cost optimization. For engineers, understanding the process constraints and performance opportunities behind the thickness of 6 μ m - why it is 6 μ m and how to choose the OD value - is more valuable than simply remembering a specification.